Container



G. A. MOORE April 7, 1959 CONTAINER Filed July 1, 1957 INVENTOR.

United States PatCflfO 2,880,924 CONTAINER George Arlington Moore, New York, N.Y. Application July 1, 1957, Serial No. 669,239

' 16 Claims. (Cl. 229-31 '-This invention relates to improvements in containers of paper-board or other sheet material, and more particularly to novel means and methods of constructing the container with integral hermetic closures on the ends thereof in order'to provide a liquid-tight structure for a container adapted to hold liquid products as well as many other various commercial commodities intended for sales distribution.

Conventional folding cartons and similar types of containers made of foldable sheet material .have a folded structure that in general must be augmented for reinforcernents by aheavy coating ofparaffine wax or, rely upon an .inserted bag liner to contain the intended prod uct. Many attempts'have been-made by the industry to improve such containers of the folding carton type wherein the end'closure for the container formed of a plurality of folded end flaps integrally related with the body walls of the container may be tightly sealed. The inner surface of the walls and fiaps in some instances have been provided with a plastic coating of protective material. Difiiculties, however, have been experienced in insuring a tight end closure due to the inherent weaknesses that are prevalent in the folded wall structure of such containers, and this weakness is well known by those skilled in the art. The converging corner ends of the wall' structure of these containers are notorious leakers and the raw cut edges of structural material exposed within the'interior ofwthe structure constitute wicks that will absorb moisture, greases and certain other ingredients of the product if directly contained therein.

.The present invention provides an improved container having a structure that is void of raw cut edge exposure within its interior and including liquid-tight converging corner end construction that constitutes one of the prime objects of the invention.

Another object of the invention is to provide in a container of the above type, a novel arrangement of closure, forming end segments upon which to construct a flat and positive hermetic closure on either or both ends of the container.

Yet another object of the invention is to provide acontainer having a folded wall structure with hermetic end closures, the interior surfaces and contiguously related junctions thereof being made substantially impervious. I

A further object of the invention is to provide a novel container blank having foldable end segments so arranged and folded into compounded marginal portions as to provide a resilient but positive pressure resisting base upon which to form the above hermetic closure.

Other objects and novel features of the invention will appear more fully hereinafter from the following detailed description when considered in connection with the accompanying drawings. It is to be expressly understood that the drawings are utilized for purposes of illustration only, and are not to be taken as a definition 2 of the limits of the invention, reference being had forthis purpose to the appended claims.

In the drawings, wherein similar reference characters refer to similar parts throughout the several views:

Fig. 1 is a broken plan view of a blank adapted to be formed into a container of the above type;

Fig. 2 is a fragmentary enlarged view partly in cross section and showing one of a pair of opposed closure forming end segments in the stage of being folded after the blank of Fig. 1 has been folded and secured in tubular body form;

Fig. 3 is a perspective view of the completed container showing the flatly disposed hermetic end closures formed;

Fig. 4 is an enlarged partial sectional view of the contaiuer shown in Fig. 3 taken along line 44 showing a structural partof the hermetic closure, and

Fig. 5 is another enlarged partial sectional view of the container taken along line 5-5 showing a transversely disposed structural partof the above closure.

' The present invention is chiefly directed to a means and method for forming a pair of improved closure panel seatingledges that resists the pressure imposed thereupon in order to effectively seal the closure forming panel or panels to the ledges in seam-tight forming relationship. The surface seal effected including also the seal of'the compounded end edges ofthe ledges that are disposed upon the corresponding interior surface portions of the opposing body side walls of the container.

To this end, each segment of a pair of opposed end segments that'are integral with each of two opposed side wall panels, is provided with a pattern coating ofadhesive on a selective area of its exterior side. The segment consists of two longitudinal marginal portions separated with 'a scored-line, the outer margin being provided with two longitudinally opposed outwardly projected integral tabs, each tab being separated from the parent margin by scored lines. The pattern coating of adhesive is applied on the exterior surface side of each'tab portion and extended inwardly to the transversely disposed scored line of the parent marginal portion of the segment. The tabsare folded on their respective scored lines outwardly and downwardly, the parent margin is folded outwardly and downwardly on its longitudinal scored line, and the inner-most longitudinal marginal portion of the segment is folded on its scored line inwardly and downwardly. The integral tabs are then further. folded inwardly and tucked in between the folded inner and outer longitudinal margins, the pattern adhesive surface portions being overlapped in surface meeting'relationship by the folding of the tab portions. Hence, the segments have been folded to form compounded three-ply marginal portions that initially are resiliently active and ultimately substantially rigid, these rigid portions being spaced inwardly of the opposite end edges of the ledges. The intermediate portionof thedoublefolded margins that extend longitudinally between the compounded portions being resilient and openly spaced. Thus, there is formed a pair of closure forming panel seating ledges having compounded opposite end edges solidly abutted upon the interior surface portions of opposing side walls effected by the overlapping panel engagement. The marginal portions disposed longitudinally between the compounded margins being resiliently co-active in effecting a positive seal of the closure.

Referring more particularly to Fig. 1, the present invention isillustrated therein as including a blank 4, the inner surface of the blank material is .preferably provided with an appliedfilm of plastic material, which film may be extruded, laminated or coated upon the inner surface of the blank as desired. One such film may consist of vinylidene chloride copolymers deposited from solution as ua e Thewallpanels7 and 9 are each provided with a foldable closure forming panel 11 and 12 respectively, to be folded on their. base scored lines 13 and14. The wall panels 8 and are each provided. with an integral and foldable end segment 15 having a base score line 16 and an out-. wardly disposed parallel score line 17 that divides the segment into an inner foldable marginal portion 18- and n Outer o bl m a por on. ,9- The. m r in 19 is provided with a pair of integral longitudinally opposed outer projected foldable tab portions 20 and each tab having a base score line 21 disposed substantially .in alignment with the intermediate freelongitudinal end edge portion of the parent margin. The outer or exterior side of each tab is provided with a coated deposit of thermoplastic adhesive a which extends inwardly to the score line 17. The. opposite side ends of the segment are provided by the effects of the slit lines 22 that separates the sides of the longitudinally opposed panels 11 and 12 from sides of the pair of segments 15. The adhesive a may be applied upon the segments-during the printing on the blankof decorative design with color inks, the pattern a constituting a laydown deposit. The bottom longitudinal end of the blank maybe provided with like-end segments 15 and panels 11 and 12 respectively, that may be ar-. ranged in alternate relative position as shown in Fig. 1 for a purpose hereinafter to be described. The blank may be folded into tubular body form in any manner desired. It is however, adapted to be folded on conventional carton folding machines and folded on certain of the score lines 5 so that the exterior surface of the wall panel 6 will overlap upon the interior surface of the wall panel 10. adhesively secured together to constitute the body seam of the container when formed of the blank. The surface of the end edge 23 of the panel 6 is adapted to be directed into abutment against the opposing interior surface portion of the wall panel 9 when forming the tubular body part of the container.

Referring now to Fig. 2, after folding and securing the blank into tubular form, the pair of oppositely disposed end segments 15' of the side walls 8 and 10 are folded to form closure panel seating ledges as follows; the tabs 20 adhesive .face it meets the corresponding adhesive face portion ofthe folded margin 19. Hence, "the tabs 20 are directed to be disposed inwardly between the opposing folded marginal portions 18 and- 19 in superimposingsurface to surface relationship as shown by the dotted lines in Fig. 2 constituting the compounded layer portions of each ledge. It will be noted that the plastic film or coating b on the exterior surface of the folded tabs 20 is directed downwardly in opposition to the corresponding exterior surface of the folded marginal portion 18. The adhesivea upon the inner disposed'surfaces of the folded margin 19 and tabs 20 meet together insurface to surfacc'relationship, and the plastic face of the margin 19 is now upwardly and flatly disposed to meet a corresponding portion of the inner plastic faceof the closure forming panel 12 when first folded on its score'line 14 and directed inwardly and downwardly :upon the flattened margins ons tu i e pane s at n lss ess .5,- Th at hstiv 4. may be activated with suitablesolvent if desiredor, the adhesive and plastic film b may be activated by exposure to radiant heat just prior to the folding of the segments 15 and then the panels 11 and 12 being folded in successive steps and into overlapping relationship disposed downwardly upon the prior folded compounded and resiliently active ledges to complete the closure.

The completed container. 24 is illustrated in Fig. 3. The constructed closure is flat and therefore well adapted to be sealed in another novel manner by engaging the surface of the folded closure. with heated belts of conveyor apparatus that may be utilized to seal the closure at any speed desired without the encumbering limitations necessary for cycle time heat exchange. In such instance, the segments 15 and panels 11 and 12 may be folded as hereinbefore described to complete the structure of the closure without activating the. adhesive a and thermoplastic .iilm b. The heated belts in contact with the exterior surface of the folded panel 11 and adiacent margins of side walls will conduct heat into the wall structure of the closure and activate the above bonding agents a and b disposed between the layers while moving the container in the conveyor through such travel distance as may be required for the heat to penetrate through the layers of the, closure to activate the agents and effect a bond thereof in seam forming relationship. The pressure imposed upon the closure may be maintained while passing the container through a chilling zone to quickly solidify the. bonding agents. However, in any manner that may be practiced for sealing the closure, pressure is to be. applied transversely and inwardly against the side walls of the container in the proximity of the compounded end edges 22 of the closure seating ledges that are disposed in abutment upon the corresponding interior plastic surface portions of the opposing side walls. The sealed structure of these abutments and overlapping panel portions is illustrated in cross section shown in Fig. 5. Due to the fact that the folded tab portions 20 of the ledges 15 are sandwiched inwardly between the contacted corresponding surfaces of the upper and lower longitudinal marginal portions of the ledges employs the novel means that compounds the triple marginal portions thereof with end edges disposed in coplanar surface relationship against the plastic face of the opposing side wall. The heat imposed upon the plastic face of the opposing side wall and to the intermediate transverse layers of plastic in the closure structure, activates the plastic material while the closure is being pressed inwardly in transverse directions as indicated by the arrows shown in Fig. 5, thereby insuring a positive liquid-tight seal constituting a hermetic closure.

The present invention stresses the above mentioned novel means forefiecting the compounded layer portions of the closure seating ledges that is productive of the hermetic type of final closure. Figs." 4 and 5 illustrate the novel structural form taken by the folding of the closure due entirely by the co-acting effects of the initial resilience of the ledges. It will be noted that the tab portions 20 are folded inwardly from the corner edge 21 of the outwardly folded marginal portion 19 and these edges being substantially coplanar with the dependent side wall. The inner disposed end edge 25 of the tab is pressed inwardly against the cushioned displaced material caused by the degrees corner fold of the margins 18 and 19. Hence, the displaced material in the corner of the fold forms a cushion gasket opposing the rigid edge 25 thereby compounding the related marginal portions into a-solid body of stratified material secured together in mass by the activated adhesive a and thermoplastic b on the built up body ends of the folded ledges. Therefore, the gap between the folded margins 18 and 19 adjacent the opposite ends thereof is filled and solidly sealed by the infolded tab portions 20. The ledge marginal portions extending longitudinally between the compounded layer portions are resiliently active having a constant tendency to spring upwardly be tween'the compounded layer end portions thereof. This springing tendency provides effective means to initially resist the downward pressure imposed by the folded closure forming panels thereby insuring firm and positive meeting surfaces of the embodied plastic adhesive materials efiiciently activated, whereby a positive bonded union of the closure is effected to constitute the hermetic closing of the container.

The pair of novel and improved closure forming seating ledges above described provides eflicient structural facility capable of forming a hermetic closure to rec tangular containers in general. The ledges also facilitate the forming of strong and sturdy cross trusses to strengthen the body structure of the container. The ledges are readily adapted to be transversely disposed in pairs as illustrated in Fig. 3. The ledges at the bottom end of the container may be formed transverse of the top end ledges. Such crossed structural feature facilitated and eflfected by the ledges materially strengthens the entire container structure to firmly arrest body twist or distortion stresses when imposed upon the container by handling or dropping. As illustrated in Figs. 4 and 5, the interior of the container is completely free of exposed raw cut edges of structural material. The conjunctive meeting edges of the plastic component material with surface portions thereof in the interior of the wall structure of the container are heat-fused together when sealing the closure, thereby constituting a seamless and substantially impervious interior surface structure of the container. The heat-fusing feature is illustrated bythe view of the corner junction 26 of the marginal portion 18 with the side wall 7 as shownin Fig. 5. A similar heat-fused junction is eifected on the edge 23 that is abutted to the plastic face of the side wall 9 of the container body structure not shown. The converg ing corner ends of the side walls and formed closure are sealed liquid-tight in seam tight forming relationship by the co-acting effects of the compounded layer sections of the closure seating ledges. by those skilled in the art, that the foldable tab portions 20 of the ledges may be longitudinally extended to any length as may be desired, even equal to the length of its parent marginal portion. However, the tabs illustrated and described herein have been purposely designed to facilitate easy folding to effectively construct the compounded-rigid layer portions adjacent the opposite ends ofthe ledges, the intermediate reversely folded marginal portions. between the ends being constructed in a manner to .be resiliently active to serve as a cushion shock absorber between the substantial rigid ends.

While the present invention has been illustrated and described with pertinent detail, it will be understood by those skilled in the art, that various changes may be made therein without departing from the general spirit of the invention. 7 Reference will therefore be had to the appended claims for a definition of the limits of the invention.) I I -What is claimed is:

l. A flat blank of foldable material adapted to:be formed into a container having a substantially square cross section and a closed end, said blank comprising a sheet of said material provided with scored lines defining five rectangular wall panels of equal width and cut to define a pair of integral multiple foldable marginal portions of end segments integral with two alternate wall panels and a pair of substantially square foldable end panels integral with two of the other of said wall pauels each segment of said pair of end segments being provided with scored lines defining two separated parallel longitudinal foldable marginal portions, the outwardly disposed margin of said foldable portions being provided with two openly spaced longitudinally opposed outwardly extended foldabletab portions, each tab having a side It should be understood cut edge extending coplanar with: 6 side out edge of said two parallel marginal portions, the outer defining surface of said pair of tabs being provided with thermoplastic adhesive that extends inwardly from the tab surface to substantially the transversely disposed center score line of said separated marginal portions.

2. A container, which comprises a folded blank into tubular body form having side walls arranged in opposing pairs, one opposing pair being provided with integral end segments, each segment having fold lines to define two longitudinally opposed triple margins with two marginal portions thereof intermediately disposed, said segment being folded with a first marginal portion thereof disposed inwardly, and downwardly substantially at right angles of it dependent side wall, the second margin being folded outwardly and downwardly in parallel relation with said first folded portion, the third folded portions consisting of two longitudinally opposed marginal portions of said second folded portionbeing disposed inwardly between the first and second folded portions to constitute a pair of opposed closure forming panel seating ledges provided with compounded opposite ends and resiliently active marginal portions thereof extended 1ongitudinally between said ends.

3. In a rectangular container having flat side walls arranged in opposing pairs, and including one pair being provided with integral end segments folded into multiple marginal portions'consisting of a first folded portion being disposed inwardly at right angles of its dependent side wall, the second portion being folded outwardly and downwardly in parallel relationship with the first folded portion, said second portion being provided with two portions thereof folded outwardly, downwardly and inwardly between the first and' second folded portions, the outer defined edges at opposite ends of the folded marginal portions being disposed in coplanar surface relationship abutted upon the corresponding interior surface portions of opposing side walls, the other pair of side walls each having an integral end closing panel, the first panel being folded inwardly and downwardly upon the up-face of said second folded marginal portion of first mentioned segments, the second panel being folded inwardly and downwardly upon the exterior surface of the first folded panel, said panels being firmly resisted by the co-acting resilience effected by said first mentioned folded segments.

4. A closure construction for containers formed of foldable sheet material which includes a pair of opposed closure panel seating ledges provided with multiple folded integral marginal portions compounded adjacent opposite ends of saidlledges, which consists of two of said marginal portions being folded so that the first folded margin is disposed inwardly and downwardly at substantially right angles of itsidependent side wall, the second folded marginal portion thereof being disposed outwardly and downwardly of its inner corner edge and in parallel surface relationship with the first folded portion, and a pair of outwardly projected tab portions folded from the outer corner edge of said second folded margins being disposed inwardly between the corresponding surface portions of the first and second folded marginal portions, the surface of a side edge of each folded tab portion being disposed in coplanar surface relationship with the extended side edge of first and second folded marginal portions, said side edges being disposed in edge to face abutment with the adjacent opposing side wall of the container, an end closing panel being disposed downwardly upon the top face of said second folded marginal portion of the ledges.

5. A closure construction for containers formed of foldable sheet material having its inner surface treated with thermoplastic adhesive material, said closure coniprising a pair of opposing closure panel seating ledges having reversely folded integral marginal portions consisting of two of said portions being folded so that the first margin is disposed inwardly and downwardly at substantially right angles of its dependent. side wall, the

second folded marginal portion thereof being disposed outwardly and downwardly in parallel surface relationship with the first folded portion, and a pair of outwardly projected tab portions being folded from the outer corner edge of said second folded margin and disposed inwardly between the first and second folded marginal portions, the opposite end edges of the seating ledges being compounded into solid body abutment upon the inner face of the adjacent opposing side wall.

6. A rectangular container comprising a tubular body portion having side walls arranged in opposing pairs and a folded bottom closure consisting of two opposed folded ledges defined with opposite ends compounded by three integral marginal portions of the dependent body side wall and folded in superimposing surface to surface relationship, the first folded margin being directed inwardly and downwardly of its dependent side-wall, the second margin being directedupwardly, outwardly and downwardly from its innerdisposedcorner edge, and two longitudinally opposed tab portions of the second margin being directed downwardly and inwardly from its outer corner edge and disposed between said first and second margins, the and edges of the three margins being abutted upon the interior surface of the adjacent opposing side wall, a closure formingpanel being folded inwardly and downwardly upon the top face of said second folded margin of the. ledges, the end edge of said panel being disposed in abutment upon the adjacent opposing side wall coplanar with the other abutted edges, and another panel being folded inwardly said edge tosurface abutments of the closure in steam forming relationship, a pair of opposing like-ledges being disposed on the top end of said body portion and arranged intransverse relationship with respect to said bottom ledges whereby, the cross trussing effects of the ledges strengthens the structure of the container to arrest distortion stresses when imposed upon the body portion thereof.

, 7. A closure construction for containers formed of folded sheet material provided with inner surface covering of thermoplastic film material and a body portion of rectangular cross section with a closed end, which comprises a pair of opposing folded ledges each integral with its dependent side wall of said. body portion, each ledge of the pair having a longitudinalmarginal portion thereof first folded inwardly and downwardly at rightangles to the dependent side wall and a second marginal portion folded upwardly, outwardly and downwardly in parallel surface relationship with the first folded portion, said second margin being provided with two longitudinally opposed integral tab portions, each tab having its outer side coated with adhesive and folded downwardly and inwardly from its outer disposed corner edge and flatly between the opposing surfaces of first and second folded marginal portions, the thermoplastic up-turnedface of the second margin being extended inwardly and downwardly upon the exterior face of the first margin by the folded, 'tab portions, said adhesive coated surface of each tab being disposed between the corresponding surface portions of the second margin and tab, the inwardly disposed end of the tab being pressed inwardly against the displaced material formed in the corner edge of the folded first and second marginal portions thereby filling the gap formed between said margins adjacent the end edges of the cornpounded portions of the defined ledges, said edges being disposed in abutment upon the inner thermoplastic face of the adjacent opposing side wall, closure forming panels of said adjacent side walls being folded in overlapping relationship upon said ledges to complete the structure of said closure, heat and pressure being applied upon the closure including the side walls in the proximity of said abutted edges, whereby. the thermoplastic film and tab 8 dhs rs s a vat ere t n h ur m we: stitute the hermetic closing of the container.

8. A container of sheet material faced on its interior surfaces with thennoplastic film coated material compri s. ing tubular body portion of substantially rectangular cross section having side walls and a fiat end closure forsaid body portion, said closure including a pair ofopposing end segments integral with a pair of said side walls, each end segment consisting of folded and marginally compounded portions defined as first and second folded margins disposed in superimposing relationship with a pair of longitudinally spaced third folded tab portions of said second folded margin being disposed inwardly between said superimposed margins, the opposite end side edges of said marginally compound folded margins being disposed in coplanar surface relationship opposed in abutment upon the thermoplastic film surface of adjacent side walls of said body portion of the container, thereby; providing a pair of closure panel seating ledges positioned inwardly at right angles of their dependent side walls, the ledge formed marginal portions adjacent their respective abutted edges to side walls being substantially solidified togther by adhesive and the marginal portions extending longitudinally between said solidified portions being non adhered and thereby rendered resiliently active when opposing the corresponding inner surface portions of the closure forming panel seated upon said ledges in seam forming relationship.

9. A container according to claim 8 wherein the longitudinal end edges of said inwardly disposed tab portionsof the ledge are abutted against the inner fillet surface portions in the degree corner fold formed of said first and second marginal portions that enclose the opposite surface sides of said tabs.

10. A container according to claim 8 wherein a first folded closure forming panel integral with its dependentside wall is seated upon said ledges, the interior thermoplastic surface of the panel having contact with 'the thermoplastic surface of the ledges, the end edge of said folded panel being aligned in coplanar surface relationship with the end edges at one end of each ledge that are abutted against the thermoplastic interior surface of one side wall of the container whereby said end edge of the panel augments the abutments of said ledge ends and forms a substantially rigid reinforcement to the abutted side wall portion extending between the ledge ends including the base corner edge of a second folded panel in tegral of the end edge opposing side wall and in overlapped relationship upon said first folded panel, said abutments to side walls being united together in seam forming relationship.

11. In a closure construction for containers of sheet material and which includes a pair ofnarrow widthyclosure panel seating ledges disposed inwardly at right angles of their corresponding side wall portions ofthe con-- tamer, each ledge being further defined as consisting of a first marginal portion being folded inwardly and downwardly ofits dependent side wall, a second marginalportron thereof being folded upwardly, outwardly and downwardly over the surface of the first folded portion, longi tudinally opposed portions integrally related to said second folded marginal portion being folded downwardly and inwardly between corresponding surface portions of; said first and second folded marginalportions, the outer opposite end edges of the folded margins being coplanar insurface relationship and thereby adapted to be uniformly abutted upon the interior surface of opposing side walls, the exterior surface of said second folded margin of the ledge being adapted to resiliently oppose surface contact with a closure forming panel and thereby self support saidpanel with resistance in order to effect a bonded unionof the engaging surfaces in seam forming relationship.

12. In a closure construction according to claim 11 wherein the interior surface of the closure forming elements being provided with thermoplastic coated material assasaa whereby the film of plastic is on the exterior face of said second folded marginal portion of the ledge and also on the bottom face of said longitudinally opposed portions integrally related thereto, the opposite surface sides thereof being provided with a coating of adhesive and upon flattening said ledges by the effects of the engaging closure forming panel being seated thereupon heated and pressed, said longitudinally opposed portions of the ledges are adhesively embedded in solidified relationship between the related portions of said first and second folded marginal portions thereby providing substantially rigid sectional portions of said ledges adjacent their respective opposite end side edges opposed by side wall portions of the container in edge to surface abutted formation.

13. In a closure construction for containers of folded and scored sheet material, which includes a pair of opposed panel seating ledges upon which the closure is constructed, each ledge defined as having a first folded marginal portion disposed inwardly at substantially right angles of its dependent side wall of the body portion of the container, a second folded marginal portion being folded and disposed resiliently active in superimposing relationship over the first folded margin and two longitudinally opposed tab portions initially projected outwardly of said second folded margin being folded inwardly between said first and second marginal portions whereby the opposite end side edges of the multiple folded margins are compounded into substantially solidified edge to face abutments upon the interior surfaces of the opposing side walls of the container in seam forming relationship, the

marginally folded portions of said ledges that are extended between said compounded portions thereof providing means for the resiliently active effects upon the corresponding surface portions of a first folded closure forming panel directed downwardly upon said ledges and which resists said panel by the co-acting effects of said resiliency in order to effect a bonded seal of the panel upon the face of the ledges.

14. In a closure construction according to claim 13 "wherein the score line upon which said first marginal portion of the ledges is folded being spaced inwardly of the adjacent transverse score line upon which said first closure forming panel is folded, said spacing further defined as being of a dimension substantially equivalent to the combined thickness of said folded marginal portions defining said ledges when engaged with said panel.

15. A fiat blank according to claim 14 wherein the fifth panel of the blank being provided with opposite end cut edges adapted to align parallel in contact with said score lines that defines said first foldable marginal portion of end segments when folding said blank to form the container, said fifth panel constituting means to form a body seam when being folded in overlapping surface relationship with the first wall panel of the blank.

16. A flat blank of foldable material having a surface covering of protective film with thermoplastic properties and adapted to be formed into a container of substantially rectangular cross section and alternate closed ends, said blank comprising a sheet of said material provided with scored lines defining substantially five rectangular wall panels and cut to define a pair of integral multiple foldable marginal portions of end segments on opposite alternate ends of two alternate pair of said wall panels and a pair of rectangular foldable end panels on the other alternate ends of said wall panels, each segment of said pairs of end segments being provided with scored lines defining two separated parallel longitudinal foldable marginal portions, the outwardly disposed margin of said portions being provided with two openly spaced longitudinally opposed outwardly extended foldable tab portions, each tab having a side out edge extending coplanar with the side cut edge of said two parallel marginal portions, the inner-most score line that defines the first foldable marginal portion of each pair of longitudinally opposed end segments being positioned in alignment each with the other and being spaced inwardly of the alternate pair of score lines that defines the folding lines of the adjacent alternate pair of longitudinally opposed rectangular end panels, said inward spacing of the aligned score lines being further defined as being of a dimension substantially equivalent to the combined thickness of said end segment when folded into said multiple marginal portions.

References Cited in the file of this patent UNITED STATES PATENTS 1,132,293 Weiss Mar. 16, 1915 2,244,282 Bergstein June 3, 1941 2,596,224 Eaton May 13, 1952 2,792,166 Brooks May 14, 1957 

